Pneumatic pump

ABSTRACT

A pneumatic pump has a valve body having a piston compartment and a receiving compartment, wherein a piston is slidably and sealedly disposed in the valve body to move between a first position and a second position. The valve body also has an exit opening communicating with the piston compartment and a resilient element to help pushing the piston to the first position. An actuator pumps air into the piston compartment and pushes the piston to the second position. The pneumatic pump further has a valve control which has a sealing member sealedly formed at the piston compartment, a driving member which is connected to the exiting opening, wherein a pressure drives the driving member automatically to unseal the sealing member to release the air inside the piston compartment to a releasing cavity and eventually allows the piston to move back to its original position.

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention

The present invention relates to a pneumatic pump, and more particularly to a pneumatic pump which has an advance structure and design featuring a more complete and efficient cycle of the piston for compressing.

2. Description of Related Arts

The pneumatic pump is used in many applications and fields such as a hydraulic jack. Pressurized air is forced into a chamber and pushes on one side of a piston to travel. A spring element installed on another side of the piston helps pushes back the piston backwardly to its original position when the application requires wherein the pressurized air are released from the chamber. The piston eventually is pushed back to its original position and completes a full cycle of the operation. A very common problem for this kind of pneumatic pump is that the pressurized air is hard to lease from the chamber and thus prevent the piston to move back to its original position to complete the full cycle. Another common problem is that the pressurized air enters and releases at a shared passage and therefore unnecessary pressures and forces will go against the motion of the piston and thus slowing the process or even make the piston not being able to travel back to its original position to complete the full cycle.

SUMMARY OF THE PRESENT INVENTION

A main object of the present invention is to provide a pneumatic pump which can ensure the pressurized air in the piston chamber to be released efficiently thus allowing the piston the move back to its original position and complete a full cycle of operation.

Another object of the present invention is to provide a pneumatic pump which the piston can travel smoothly and efficiently during the operation.

Another object of the present invention is to provide a pneumatic pump which the pressurized air can be released from the piston chamber automatically and does not require a complicated mechanical structure.

Another object of the present invention is to provide a pneumatic pump which uses two separate passages for releasing the pressurized air into and out from the piston chamber to reduce unnecessary pressures and forces acting on the piston so as to provide a smoother and more efficient cycle of the traveling piston.

Another object of the present invention is to provide a pneumatic pump which is simple in structure and does not require complicated mechanical parts for assembling thus reduce the cost of manufacturing or repairing.

Another object of the present invention is to provide a pneumatic pump which has an advance design for the contacting side wall of the piston so as to reduce the friction caused by traveling along a valve body thus helping the machine to be more efficient.

Accordingly, in order to accomplish the above objects, the present invention provides a pneumatic pump comprising:

a valve body having a valve chamber defining a rear piston compartment and a front receiving compartment, and an air exiting passage having an exit opening communicating with the valve chamber for releasing air therewithin;

a piston sealedly disposed in the valve body between the piston cavity and the receiving cavity in a slidably movable manner;

an actuator for pumping the air into the valve chamber of the valve body to forwardly move the piston from a first position to a second position;

a resilient element disposed in the receiving compartment for applying an urging force against the piston to backwardly push the piston from the second position back to the first position;

a valve control, which is sealedly mounted to the valve body to sealedly enclose the valve chamber, comprising:

a pressuring arrangement having a releasing cavity communicating with the piston compartment and a control cavity communicating with the valve chamber through the air exiting passage for controlling a pressure between the piston compartment and the control cavity

a sealing member sealedly mounted at the releasing cavity in a slidably movable manner for preventing air flowing from the piston compartment to the releasing cavity;

a driving member sealedly disposed in the control cavity in a slidably movable manner to divide the control cavity into a first compartment and a second compartment, wherein the driving member is coupled with the sealing member to drive the sealing member to slidably unseal the releasing cavity; and

an air discharging passage extended from the releasing cavity for discharging the air therewithin, wherein when the actuator pumps the air into the valve chamber to push the piston until the piston cavity is communicating with the exit opening of the air exiting passage, the air within the piston cavity is released to the second compartment of the control cavity, wherein when the pressure within the piston cavity is balanced with the pressure of the second compartment, the driving member is pressurized to push the sealing member to slidably unseal the releasing cavity for releasing the air therewithin through the air discharging passage, wherein when the piston is pushed by the resilient element back to the first position and to seal with the exit opening, the air within the piston cavity is forced to release to the air discharging passage through the releasing cavity until the sealing member is pushed by the piston to seal the releasing cavity so as to minimize the pressure of the piston cavity to ensure the piston moves back to the first position.

These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of the pneumatic pump according to a preferred embodiment of the present invention.

FIG. 2 is a front view of the valve control of the pneumatic pump according to the preferred embodiment of the present invention.

FIG. 3 is a cross sectional view of the valve control of the pneumatic pump according to the preferred embodiment of the present invention.

FIG. 4 is another cross sectional view of the valve control of the pneumatic pump according to the preferred embodiment of the present invention.

FIG. 5 is a cross sectional view of the piston of the pneumatic pump according to the preferred embodiment of the present invention.

FIG. 6 is a top view of the piston of the pneumatic pump according to the preferred embodiment of the present invention.

FIG. 7 illustrates an alternative mode of the piston of the pneumatic pump according to the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

According to the preferred embodiment of the present invention as shown in FIG. 1 to 4 of the drawings, a pneumatic pump comprises a valve body 1 made of rigid metallic metals so it can withstand a pressure within. The valve body 1 has a valve chamber defining a rear piston compartment 13 and a front receiving compartment 12. The valve body further comprises an air exiting passage 11 having an exit opening 111 communicating with the valve chamber for releasing air therewithin. The valve body 1 further comprises a sidewall 21 and a tubular wall having two ends sealedly mounted at the sidewall 21 and a valve control 4 to define the valve chamber within the tubular wall.

The pneumatic pump further comprises a piston 31 made of nylon sealedly disposed in the valve chamber of the valve body 1 in a slidably movable manner to define the piston compartment 13 and the receiving compartment 12. Accordingly, the piston compartment 13 is defined within the piston 31, the tubular wall and the valve control 4 while the receiving compartment 12 is defined within the piston 31, the tubular wall and the sidewall 21. The air exiting passage 11 is enclosedly embedded along the tubular wall at a position that the exit opening 111 is formed at an inner surface of the tubular wall to communicate with the valve chamber.

The piston 31 is at rest in the beginning at a position which minimizes a volume of the rear piston compartment 13 and this position is regarded as a first position. A second position is formed when the piston 31 is at a position which minimizes a volume of the front receiving compartment 12. In other words, the sliding movement of the piston 31 within the valve chamber will correspondingly change the volumes of the piston compartment 13 and the receiving compartment 12.

The piston 31 comprises a sealing ring 32 and a spaced apart guiding ring 33 coaxially mounted at an outer circumferential wall of the piston 31 to sealedly contact with an inner circumferential wall of the valve chamber. A sliding groove 311 is indently formed around the outer circumferential wall of the piston 31 between the sealing ring 32 and the guiding ring 33 to define a gap formed between the outer circumferential wall of the piston 31 and the inner circumferential wall of the valve chamber and to reduce a surface friction against the inner circumferential wall so as to allow the piston 31 to slide within the valve chamber smoothly.

The pneumatic pump further has a resilient element 6 disposed in the receiving compartment 12 for applying an urging force against the piston 31. The resilient element 6 comprises a compression spring wherein two ends of the compression spring 6 are attached to a front end of the piston 31 and to a rear end of sidewall 21. The compression spring 6 compresses when the piston 31 moves from the first position to the second position and applies an urging force against the piston 31 to help pushing the piston 31 back to the first position.

The sidewall 21 of the valve body 1 forms a valve cover sealedly installed at a front end of the valve body 1 to ensure the receiving compartment 12 by sealedly enclosed. The sidewall 21 comprises a holding seat 22 protruding therefrom to hold the respective end of the resilient element 6 in position and a sealing shaft element 23, having a sealing shaft passage 24, coaxially extended from the holding seat 22, wherein a guiding shaft 5 is slidably passing through the sealing shaft passage 24 to attach to the piston 31 to guide the sliding movement of the piston 31 within the valve chamber. In other words, when the piston 31 is slid within the valve chamber, the guiding shaft 5 is correspondingly slid along the sealing shaft passage 24 to stabilize the sliding movement of the piston 31.

The pneumatic pump further comprises an actuator 7 for pumping air into the valve chamber of the valve body 1. Air that is forced into the valve chamber of the valve body 1 becomes pressurized in the piston compartment 13. The pressurized air creates a surface pushing force on the piston 31 and thus pushes the piston 31 to move forwardly from the first position to the second position.

The valve control 4 sealedly mounted to the corresponding end of the valve body 1 to sealedly enclose the valve chamber. The valve control 4 has a pressuring arrangement which comprises a releasing cavity formed at a rear end of the rear piston compartment 13 and defined a first cavity portion 46 and a second cavity portion 47. The releasing cavity communicates with the rear piston compartment 13. The valve control 4 further comprises a control cavity 43 communicating with the valve chamber through the air exiting passage 11 for controlling a pressure between the piston compartment 13 and the control cavity 43. An air guiding passage 45 extended from the control cavity 43 to align with the air exiting passage 11 for guiding the air along the air exiting passage 11 to the control cavity 43 through the air guiding passage 45. In other words, the piston compartment 13 and the control cavity 43 are linked by the air exiting passage 11 and the air guiding passage 45. The control valve 4 further comprises an air inputting passage 411 connecting between the actuator 7 and the first cavity portion 46 allowing the air to be pumped into the valve chamber of the valve body 1.

The valve control 4 further comprises a sealing member 48 sealedly mounted at the control cavity 43 in a slidably movable manner for preventing air flowing from the rear piston compartment 13 to the releasing cavity. The sealing member 48 has a larger circumferential size than the second cavity portion 47 but has a smaller circumferential size than a driving member 44 which is sealedly disposed in the control cavity 43 in a slidably movable manner.

The valve control further comprises a driving shaft 434 coupling between the sealing member 48 and the driving member 44 such that when the driving member is 44 is pushed forwardly, the sealing member 48 is concurrently moved via the driving shaft 434 to unseal the releasing cavity. While in the first position, the control shaft 434 and sealing member 48 ensure the piston compartment 13 is completely sealed and thus the air can be accumulated and become pressurized therewithin. The circumferential size of the control shaft 434 is smaller than the second cavity portion 47.

The driving member 44 in a slidably manner divides the control cavity 43 into a first compartment 431 and a second compartment 432. The control cavity 43 further comprises a releasing channel 433 extended from the first compartment 431 and connects with and is an independent releasing channel. Accordingly, air guiding passage 45 extended from the second compartment 432 of the control cavity 43.

The valve control 4 further comprises an air discharging passage 42 extended from the releasing cavity for discharging the air therewithin. When the actuator 7 pumps air into the valve chamber to push the piston 31 until the piston compartment 13 is communicating with the exit opening 111 of the air exiting passage 11, the air within the piston compartment 13 is released to the second compartment 432 of the releasing cavity. At that situation, the piston compartment 13, the exiting opening 111, the air exiting passage 11, the air exiting channel 45, and the second compartment 432 are all connected together and thus the air pressure of the rear piston compartment 13 is balanced with the air pressure of the second compartment 432. Since the circumferential size of the sealing member 48 is smaller than the circumferential size of the driving member 44, the pressure will exerts a larger surface force and drive the driving member 44 to move forward and push the sealing member 48 to move forward automatically as well to unseal the rear piston compartment 13. The rear piston compartment 13 is now connected to the second cavity portion 47 and the air discharging passage 42 and pressurized air can be released. When the pressurized air is starting to release, the piston 31 is pushed by the resilient element back toward the first position. At a point while the piston 31 is moving backward, the piston 31 will once again seal the exiting opening 111 of the air exiting passage 11. The air within the rear piston compartment 13 is forced to release to the air discharging passage 42 through the releasing cavity until the sealing member 48 is pushed by the piston to seal the releasing cavity so as to minimize the pressure of the piston compartment 13 to ensure the piston moves back to the first position.

In other words, the first cavity portion 46 of the releasing cavity has a circumferential size corresponding to a size of the sealing member 48 for the sealing member 48 sealedly sliding at the first cavity portion 46. The second cavity portion 47 of the releasing cavity, having a circumferential size smaller than the circumferential size of the first cavity portion 46, communicating with the air discharging passage 42 such that when the sealing member is slidably pushed to seal at the first cavity portion 46 of the releasing cavity, the air within the releasing cavity is released to the air discharging passage 42 through the second cavity portion 47 of the releasing cavity.

According to FIGS. 5 and 6 of the drawings, it is worth to mention that the piston 31 has a pusher wall 312 arranged so that when the air is pumped into the rear piston compartment 13, the piston 31 is pushed forward until the pusher wall 312 thereof is positioned in front of the exit opening 111. When the air within the rear piston compartment 13 is released through the air discharging passage, the piston 31 is pushed backward until the pusher wall 312 thereof pushes the sealing member to seal at the releasing cavity. The pusher wall 312 further has a plurality of balancing slots 313 indented into the pusher wall 312 so as to help balancing the movement of the piston 31 thus to provide a smoother movement.

As shown in FIG. 7, the piston 31 further has a pressuring passage 314 formed on the outer circumferential wall of the piston 31 to communicate the piston compartment 13 with the receiving compartment 12. When there is a slight pressure release from the sealing ring 32 of the piston 31, the air can now be led from the piston compartment 13 to the receiving compartment 12. This process will not lead the pressurize air into the exiting opening 111 which leads to the releasing cavity and starts to push the sealing member 48 at a premature stage. Releasing some of the air to the receiving compartment 12 also helps to decrease the friction inside the releasing cavity and thus helps the piston 31 to move back to the first position efficiently.

It is worth to mention that the releasing channel 433 is capable to release pressurized air from the first compartment 431 independently from the discharging passage 42 extended from the releasing cavity. The reason is to prevent the sealing member 48 seals the rear piston compartment 13 at a premature stage and thus preventing the piston 31 to move back to the first position and complete a full cycle. This process also helps the piston 31 to move back more efficiently.

One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.

It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims. 

1. A pneumatic pump, comprising: a valve body having a valve chamber defining a rear piston compartment and a front receiving compartment, and an air exiting passage having an exit opening communicating with said valve chamber for releasing air therewithin; a piston sealedly disposed in said valve body between said rear piston compartment and said front receiving compartment in a slidably movable manner; an actuator for pumping said air into said valve chamber of said valve body to forwardly move said piston from a first position to a second position; a resilient element disposed in said receiving compartment for applying an urging force against said piston to backwardly push said piston from said second position back to said first position; a valve control, which is sealedly mounted to said valve body to sealedly enclose said valve chamber, comprising: a pressuring arrangement having a releasing cavity communicating with said piston compartment and a control cavity communicating with said valve chamber through said air exiting passage for controlling a pressure between said rear piston compartment and said control cavity; a sealing member sealedly mounted at said releasing cavity in a slidably movable manner for preventing air flowing from said rear piston compartment to said releasing cavity; a driving member sealedly disposed in said control cavity in a slidably movable manner to divide said control cavity into a first compartment and a second compartment, wherein said driving member is coupled with said sealing member to drive said sealing member to slidably unseal said releasing cavity; and an air discharging passage extended from said releasing cavity for discharging said air therewithin, wherein when said actuator pumps said air into said valve chamber to push said piston until said rear piston compartment is communicating with said exit opening of said air exiting passage, said air within said rear piston compartment is released to said second compartment of said control cavity, wherein when said pressure within said rear piston compartment is balanced with said pressure of said second compartment, said driving member is pressurized to push said sealing member to slidably unseal said releasing cavity for releasing said air therewithin through said air discharging passage, wherein when said piston is pushed by said resilient element back to said first position and to seal with said exit opening, said air within said rear piston compartment is forced to release to said air discharging passage through said releasing cavity until said sealing member is pushed by said piston to seal said releasing cavity so as to minimize said pressure of said rear piston compartment to ensure said piston moves back to said first position.
 2. The pneumatic pump, as recited in claim 1, wherein a circumferential size of said driving member is larger than a circumferential size of said sealing member such that under a balanced pressure between said second compartment and said rear piston compartment, said driving member is pushed forwardly to drive said sealing member to unseal said releasing cavity.
 3. The pneumatic pump, as recited in claim 1, wherein said releasing cavity has a first cavity portion having a circumferential size corresponding to a size of said sealing member for said sealing member sealedly sliding at said first cavity portion, and a second cavity portion, having a circumferential size smaller than said circumferential size of said first cavity portion, communicating with said air discharging passage such that when said sealing member is slidably pushed to seal at said first cavity portion of said releasing cavity, said air within said releasing cavity is released to said air discharging passage through said second cavity portion of said releasing cavity.
 4. The pneumatic pump, as recited in claim 2, wherein said releasing cavity has a first cavity portion having a circumferential size corresponding to a size of said sealing member for said sealing member sealedly sliding at said first cavity portion, and a second cavity portion, having a circumferential size smaller than said circumferential size of said first cavity portion, communicating with said air discharging passage such that when said sealing member is slidably pushed to seal at said first cavity portion of said releasing cavity, said air within said releasing cavity is released to said air discharging passage through said second cavity portion of said releasing cavity.
 5. The pneumatic pump, as recited in claim 1, wherein said exit opening is formed at said valve body at a position that when said piston is backwardly moved to locate at said first position, said receiving cavity is communicating with said air exiting passage via said exit opening while a volume of said rear piston compartment is minimized, wherein when said piston is forwardly moved to locate at said second position, said piston compartment is communicating with said air exiting passage via said exit opening while a volume of said receiving compartment is minimized.
 6. The pneumatic pump, as recited in claim 4, wherein said exit opening is formed at said valve body at a position that when said piston is backwardly moved to locate at said first position, said receiving cavity is communicating with said air exiting passage via said exit opening while a volume of said rear piston compartment is minimized, wherein when said piston is forwardly moved to locate at said second position, said piston compartment is communicating with said air exiting passage via said exit opening while a volume of said receiving compartment is minimized.
 7. The pneumatic pump, as recited in claim 1, wherein said valve control further has an air guiding passage extended from said control cavity to align with said air exiting passage for guiding said air along said air exiting passage to said control cavity through said air guiding passage.
 8. The pneumatic pump, as recited in claim 6, wherein said valve control further has an air guiding passage extended from said control cavity to align with said air exiting passage for guiding said air along said air exiting passage to said control cavity through said air guiding passage.
 9. The pneumatic pump, as recited in claim 1, wherein said valve control further comprises a driving shaft coupling between said sealing member and said driving member such that when said driving member is pushed forwardly, said sealing member is concurrently moved via said driving shaft to unseal said releasing cavity.
 10. The pneumatic pump, as recited in claim 8, wherein said valve control further comprises a driving shaft coupling between said sealing member and said driving member such that when said driving member is pushed forwardly, said sealing member is concurrently moved via said driving shaft to unseal said releasing cavity.
 11. The pneumatic pump, as recited in claim 1, wherein said valve body comprises a sidewall and a tubular wall having two ends sealedly mounted at said sidewall and said valve control to define said valve chamber within said tubular wall, wherein said piston compartment is defined within said piston, said tubular wall and said valve control while said receiving compartment is defined within said piston, said tubular wall and said sidewall.
 12. The pneumatic pump, as recited in claim 10, wherein said valve body comprises a sidewall and a tubular wall having two ends sealedly mounted at said sidewall and said valve control to define said valve chamber within said tubular wall, wherein said piston compartment is defined within said piston, said tubular wall and said valve control while said receiving compartment is defined within said piston, said tubular wall and said sidewall.
 13. The pneumatic pump, as recited in claim 11, wherein said air exiting passage is enclosedly embedded along said tubular wall at a position that said exit opening is formed at an inner surface of said tubular wall to communicate with said valve chamber.
 14. The pneumatic pump, as recited in claim 12, wherein said air exiting passage is enclosedly embedded along said tubular wall at a position that said exit opening is formed at an inner surface of said tubular wall to communicate with said valve chamber.
 15. The pneumatic pump, as recited in claim 12, wherein said resilient element comprises a compression spring having two ends biasing against said sidewall and said piston to push said piston towards said valve control so as to ensure said piston slidably moving back to said first position from said second position.
 16. The pneumatic pump, as recited in claim 14, wherein said resilient element comprises a compression spring having two ends biasing against said sidewall and said piston to push said piston towards said valve control so as to ensure said piston slidably moving back to said first position from said second position.
 17. The pneumatic pump, as recited in claim 1, wherein said piston further comprises a sealing ring and a spaced apart guiding ring coaxially mounted at an outer circumferential wall of said piston to sealedly contact with an inner circumferential wall of said valve chamber, wherein a sliding groove is indently formed around said outer circumferential wall of said piston between said sealing ring and said guiding ring to define a gap is formed between said outer circumferential wall of said piston and said inner circumferential wall of said valve chamber so as to allow said piston to slide within said valve chamber smoothly.
 18. The pneumatic pump, as recited in claim 16, wherein said piston further comprises a sealing ring and a spaced apart guiding ring coaxially mounted at an outer circumferential wall of said piston to sealedly contact with an inner circumferential wall of said valve chamber, wherein a sliding groove is indently formed around said outer circumferential wall of said piston between said sealing ring and said guiding ring to define a gap is formed between said outer circumferential wall of said piston and said inner circumferential wall of said valve chamber so as to allow said piston to slide within said valve chamber smoothly.
 19. The pneumatic pump, as recited in claim 18, wherein said piston further comprises a sealing ring and a spaced apart guiding ring coaxially mounted at an outer circumferential wall of said piston to sealedly contact with an inner circumferential wall of said valve chamber, wherein a sliding groove is indently formed around said outer circumferential wall of said piston between said sealing ring and said guiding ring to define a gap is formed between said outer circumferential wall of said piston and said inner circumferential wall of said valve chamber so as to allow said piston to slide within said valve chamber smoothly.
 20. The pneumatic pump, as recited in claim 19, wherein said piston further has a pressuring passage formed thereon to communicate with said piston compartment with said receiving compartment for allowing said piston moving back to said first position rapidly. 